Black Haired Girl Making Soap Bubbles Down By The Lake

Merging
When two bubbles merge, the same physical principles apply, and the bubbles will adopt the shape with the smallest possible surface area. Their common wall will bulge into the larger bubble, as smaller bubbles have a higher internal pressure (also known as Ostwald ripening which is caused by pressure differences in bubbles of different radii as predicted by the Young–Laplace equation). If the bubbles are of equal size, the wall will be flat.
At a point where three or more bubbles meet, they sort themselves out so that only three bubble walls meet along a line. Since the surface tension is the same in each of the three surfaces, the three angles between them must be equal to 120°. This is the most efficient choice, again, which is also the reason why the cells of a beehive have the same 120° angle and form hexagons. Only four bubble walls can meet at a point, with the lines where triplets of bubble walls meet separated by cos−1(−1/3) ≈ 109.47°.